The present invention relates generally a process for treating textile substrates, and more particularly to a process for treating a textile substrate in treatment bath having a transport material entrained therein, the transport material having a treatment material dissolved, dispersed or suspended therein. In a preferred embodiment, the process comprises treating a textile substrate in supercritical fluid carbon dioxide (SCFxe2x80x94CO2).
It will be appreciated by those having ordinary skill in the art that conventional aqueous dyeing processes for textile substrates generally provide for effective dyeing, but possess many economic and environmental drawbacks. Particularly, aqueous dye baths that include organic dyes and co-solvents must be disposed of according to arduous environmental standards. Compliance with environmental regulations and process heating requirements thus drive up the costs of aqueous textile dyeing to both industry and the consuming public alike. Accordingly, there is a substantial need in the art for an alternative dyeing process wherein such problems are avoided.
One alternative to aqueous dyeing that has been proposed in the art is the dyeing of textile substrates in a supercritical fluid. Particularly, textile dyeing processes using supercritical fluid carbon dioxide (SCFxe2x80x94CO2) have been explored.
However, those in the art who have attempted to treat textile substrates in SCFxe2x80x94CO2 have encountered a variety of problems. These problems include, but are not limited to, xe2x80x9ccrockingxe2x80x9d (i.e. tendency of a dye to smudge when a dyed article is touched) of a dye on a dyed textile article; unwanted deposition of the dye onto the article and/or onto the dyeing apparatus during process termination; difficulty in characterizing solubility of the dyes in SCFxe2x80x94CO2; insolubility of many dyes and other treatment materials in CO2; difficulty introducing the dyes into the SCFxe2x80x94CO2 flow; difficulty in preparing the dyes for introduction into the dyeing process; high pressure and temperature requirements for solubility; and trimer (cyclic oligomer) extraction from polyester at high temperature. These problems are exacerbated when attempts to extrapolate from a laboratory process to a plant-suitable process are made.
Poulakis et al., Chemiefasern/Textilindustrie, Vol. 43-93, February 1991, pages 142-147 discuss the phase dynamics of supercritical carbon dioxide. An experimental section describing an apparatus and process for dyeing polyester in supercritical carbon dioxide in a laboratory setting is also presented. Thus, this reference only generally describes the dyeing of polyester with supercritical carbon dioxide in the laboratory setting and is therefore believed to be limited in practical application.
U.S. Pat. No. 5,199,956 issued to Schlenker et al. on Apr. 6, 1993 describes a process for dyeing hydrophobic textile substrate with disperse dyes by heating the disperse dyes and textile substrate in SCFxe2x80x94CO2 with an azo dye having a variety of chemical structures. The patent thus attempts to provide an improved SCFxe2x80x94CO2 dyeing process by providing a variety of dyes for use in such a process.
U.S. Pat. No. 5,250,078 issued to Saus et al. on Oct. 5, 1993 describes a process for dyeing hydrophobic textile substrate with disperse dyes by heating the disperse dyes and textile substrate in SCFxe2x80x94CO2 under a pressure of 73 to 400 bar at a temperature in the range from 80xc2x0 C. to 300xc2x0 C. Then the pressure and temperature are lowered to below the critical pressure and the critical temperature, wherein the pressure reduction is carried out in a plurality of steps.
U.S. Pat. No. 5,578,088 issued to Schrell et al. on Nov. 26, 1996 describes a process for dyeing cellulose fibers or a mixture of cellulose and polyester fibers, wherein the fiber material is first modified by reacting the fibers with one or more compounds containing amino groups, with a fiber-reactive disperse dyestuff in SCFxe2x80x94CO2 at a temperature of 70-210xc2x0 C. and a CO2 pressure of 30-400 bar. Specific examples of the compounds containing amino groups are also disclosed. Thus, this patent attempts to provide level and deep dyeings by chemically altering the fibers prior to dyeing in SCFxe2x80x94CO2.
U.S. Pat. No. 5,298,032 issued to Schlenker et al. on Mar. 29, 1994 describes a process for dyeing cellulosic textile substrate, wherein the textile substrate is pretreated with an auxiliary composition that promotes dye uptake subsequent to dyeing, under pressure and at a temperature of at least 90xc2x0 C. with a disperse dye from SCFxe2x80x94CO2. The auxiliary composition is described as being preferably polyethylene glycol. Thus, this patent attempts to provide improved SCFxe2x80x94CO2 dyeing by pretreating the material to be dyed.
Despite extensive research into SCFxe2x80x94CO2 textile treatment processes, there remains room for improvement in the development of a process for treating a textile substrate with a textile treatment material. A process for treating a textile substrate would be particularly desirable in a plant-scale application of an SCFxe2x80x94CO2 textile treatment process. Therefore, the development of such a process meets a long-felt and significant need in the art.
A process for treating a textile substrate is disclosed. The process comprises providing a textile substrate; providing a treatment bath; entraining a transport material in the treatment bath wherein the transport material further comprises a treatment material dissolved, dispersed or suspended therein and wherein the transport material is substantially immiscible with the treatment bath; and contacting the textile substrate with the transport material in the treatment bath to thereby treat the textile substrate with the treatment material in the transport material. In a preferred embodiment, the process comprises treating a textile substrate in supercritical fluid carbon dioxide (SCFxe2x80x94CO2).
Accordingly, it is an object of the present invention to provide a novel process for treating a textile substrate. This object is achieved in whole or in part by the present invention.
An object of the invention having been stated hereinabove, other objects will be evident as the description proceeds, when taken in connection with the accompanying Drawings and Laboratory Examples as best described hereinbelow.